<https://kotlinlang.org/docs/reference/extensions....

# android

[jw]

https://kotlinlang.org/docs/reference/extensions.html

[yaakov]

Do I just create a new kt file like this?

package foo.bar

fun Baz.goo(){ ... }

[yaakov]

Oh okay, so I create a file called extensions and ooooooooh. Okay okay, this is good.

[bachhuberdesign]

Example for Bitmaps https://github.com/milkcan/effortless-android/blob/master/effortless-android-base/src/main/java/io/milkcan/effortlessandroid/BitmapExtensions.kt

[bachhuberdesign]

If you add @file:JvmName("SomeExtensionFile") you will be able to call from Java as well (if your codebase is mixed)

[yaakov]

@bachhuberdesign Is that your repo?

[bachhuberdesign]

Yep, just a selection of extensions that I use for personal projects

[yaakov]

lmao look at my resize extension, it's the exact same as yours:

fun Bitmap.resize(image: Bitmap, maxWidth: Int = 1920, maxHeight: Int = 1080): Bitmap {
    if (maxHeight > 0 && maxWidth > 0) {
        val width = image.getWidth()
        val height = image.getHeight()
        val ratioBitmap = width.toFloat() / height.toFloat()
        val  ratioMax = maxWidth.toFloat() / maxHeight.toFloat()
        var finalWidth = maxWidth
        var  finalHeight = maxHeight

        if (ratioMax > ratioBitmap) {
            finalWidth = (maxHeight.toFloat() * ratioBitmap).toInt()
        } else {
            finalHeight = (maxWidth.toFloat() / ratioBitmap).toInt()
        }
        var finalimage = Bitmap.createScaledBitmap(image, finalWidth, finalHeight, true)
        return finalimage
    } else {
        return image
    }
}

[bachhuberdesign]

Nice, thank you StackOverflow 😂

[yaakov]

I steal a solid 20% of my code, no worries.

[yaakov]

StackOverflow is like MIT license anyways. Right? 😉

[bachhuberdesign]

I'm hoping eventually the Android team at Google releases an "official" extension library so I don't need to drop this or Anko into my projects

[yaakov]

Am I supposed to only use extensions on objects themselves? It's a shame I can't Bitmap.resize()

[yaakov]

Looks like I can only call myBitmap.resize()

[bachhuberdesign]

If you wanted to call it like that, you could just write a static method and pass in your Bitmap

[bachhuberdesign]

instead of extension

[yaakov]

I didn't think kotlin had static methods, just companion objects.

[bachhuberdesign]

You can use @JvmStatic annotation

[bachhuberdesign]

https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.jvm/-jvm-static/

[bachhuberdesign]

If you use that annotation it needs to be inside a companion object or top level object though

[yaakov]

Yeah I'm looking it up now. Never used the annotation tags tbh

[yaakov]

So I'd have to pass the static method when I declare the bitmap or?

[bachhuberdesign]

I mainly use it for Fragment instances i.e.

companion object {
        @JvmStatic
        fun newInstance(someInt: Int): SomeFragment {
            val fragment = SomeFragment()

            val bundle = Bundle()
            bundle.putInt(SOME_KEY, someInt)
            fragment.arguments = bundle

            return fragment
        }
    }

[bachhuberdesign]

What do you mean?

[bachhuberdesign]

If you wanted static you could do

object BitmapHelper {
    
    @JvmStatic
    fun createScaledBitmap(): Bitmap {
        // TODO: 
    }
    
}

and then call BitmapHelper.createScaledBitmap()

[bachhuberdesign]

Extension is probably cleaner though

[yaakov]

I guess extensions work for now.